Carbonyl J Acid Derivatives Block Protein Priming of Hepadnaviral P Protein and DNA-Dependent DNA Synthesis Activity of Hepadnaviral Nucleocapsids
Carbonyl J Acid Derivatives Block Protein Priming of Hepadnaviral P Protein and DNA-Dependent DNA Synthesis Activity of Hepadnaviral Nucleocapsids
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DOI：
10.1128/jvi.00816-12
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发表时间：
2012-07
影响因子：
5.4
通讯作者：
Yong-Xiang Wang;Y. Wen;M. Nassal
中科院分区：
文献类型：
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作者：
Yong-Xiang Wang;Y. Wen;M. Nassal
摘要目前慢性B型肝炎的治疗仅对一小部分患者有效。所有获批的直接抗病毒药物都是靶向B型肝炎病毒（HBV）P蛋白的DNA聚合酶活性的核苷（酸）类似物（NA）;耐药性和交叉耐药性可能限制其长期适用性。P蛋白是一种不常见的逆转录酶，它通过蛋白质引发启动逆转录，通过蛋白质引发，独特的末端蛋白质结构域中的Tyr残基充当第一个DNA核苷酸的受体。引发需要P蛋白与前基因组RNA（pgRNA）模板上的ε茎环结合。这种相互作用还介导pgRNA的糖苷化，因此提供了特别有吸引力的干预靶标。利用可用于鸭HBV（DHBV）而非HBV的体外引发系统，我们证明羰基J酸家族的萘脲，特别是KM-1，通过靶向P蛋白并干扰P-DHBV ε起始复合物的形成而有效地抑制蛋白引发。定量评估显示，成熟过程中复合物稳定性显著增加，但即使是引发的复合物对KM-1浓度低于10 μM仍保持敏感。此外，KM-1抑制DHBV和HBV核衣壳的DNA依赖性DNA聚合酶活性，包括来自拉米夫定耐药变体的DNA聚合酶活性，直接证明了人HBV对该化合物的敏感性。抗细胞中病毒复制的活性较低，可能是由于细胞内可用性较低。因此，KM-1还不是一种候选药物，但其独特的作用机制表明，它是开发改进的、治疗上适用的衍生物的非常有用的先导物。
ABSTRACT Current treatments for chronic hepatitis B are effective in only a fraction of patients. All approved directly antiviral agents are nucleos(t)ide analogs (NAs) that target the DNA polymerase activity of the hepatitis B virus (HBV) P protein; resistance and cross-resistance may limit their long-term applicability. P protein is an unusual reverse transcriptase that initiates reverse transcription by protein priming, by which a Tyr residue in the unique terminal protein domain acts as an acceptor of the first DNA nucleotide. Priming requires P protein binding to the ε stem-loop on the pregenomic RNA (pgRNA) template. This interaction also mediates pgRNA encapsidation and thus provides a particularly attractive target for intervention. Exploiting in vitro priming systems available for duck HBV (DHBV) but not HBV, we demonstrate that naphthylureas of the carbonyl J acid family, in particular KM-1, potently suppress protein priming by targeting P protein and interfering with the formation of P-DHBV ε initiation complexes. Quantitative evaluation revealed a significant increase in complex stability during maturation, yet even primed complexes remained sensitive to KM-1 concentrations below 10 μM. Furthermore, KM-1 inhibited the DNA-dependent DNA polymerase activity of both DHBV and HBV nucleocapsids, including from a lamivudine-resistant variant, directly demonstrating the sensitivity of human HBV to the compound. Activity against viral replication in cells was low, likely due to low intracellular availability. KM-1 is thus not yet a drug candidate, but its distinct mechanism of action suggests that it is a highly useful lead for developing improved, therapeutically applicable derivatives.